When you last caught up with the Xteam Keltoi it was 110 AD, we had just traded for Gunpowder and found out that the saltpeter was safely tucked away in places like Japan and France. We had established a second core around Beijing and were at war with the Mongols.
The war against the Mongols lasted until 410 AD, leaving them with one city. During this time the Keltoi ... the wannabe Cutlural Kings of the Entire Planet .. lost two cities in flips to Japan and India. We traded up to Physics and Metallurgy in 420 AD, and started up our own research for Military Tradition, In 450 AD, having tried peace for all of 4 turns, we'd had enough of that and needed to get some more space, and some saltpeter. We also needed to get some action going in the north to slow France, America and Babylon down. So a complex sequence of alliances and declarations saw the world in a state of armed conflict. Our initial active targets were Japan and Carthage. Iroquois and France - the owners of the Pyramids - would come later.
During the next few hundred years, by 850 AD, we took out Japan and the remnants of Mongolia, and consigned the Iroquois and Carthage to small seaside resorts. And we prepared to invade France. Meanwhile, we built cities galore and worked out how we would use Communistic pop rushing to create a cultural megalopolis.
In 980 AD General Gator 13th declared war on France and took Paris with the Pyramids, Leos and Smiths. We proceeded to expand our territory at France's expense, and in 1030 AD we revolted to Communism and started the Rush for Culture in earnest. From then on it was a micromanagement-fest. We'd been irrigating and railing every blade of grass, sod of earth and grain of sand for a while, and we had to made optimum use of all that food to build population to create more towns, more buildings, more drafted rifles. Fortunately we had six of us to do it, and each only had to take one or two turn sets of really intensive culture rush activity. We had also managed to accumulate a sizeable treasury of over 6K gold, and this stood us in good stead as our cultural maintenance costs rose.
During the last five turns General Gyathaar - normally our Cultural Attaché - had a few cliff-hanging turns when the Babylonians decided to try to put a stop to our cultural hegemony. By that time we were going too fast for them to affect the outcome, but we did lose a few towns on our borders.
Bottom line statistics:
392 towns
3095 Culture per turn
100125 culture at 1385 AD
Firaxis score - 9108
296 units, of which 184 were workers or slaves
Here's what almost 400 cities look like: